1. Field of the Invention
The present invention relates to an assembly for cutting a hole and, most particularly, to an assembly for cutting a hole in a pipe or in a well casing.
2. Background Information
There are many instances wherein it is necessary to drill a hole in the sidewall of an existing conduit such as a pipe, a well casing, or the like. In most cases, this operation is performed in new construction or in conjunction with a modification of an existing plumbing system. For example, when drilling a well, it is standard practice to provide a below ground level discharge in the well casing for the water at a depth below the deepest penetration of frost in winter. This prevents the water from freezing when pumped close to the surface from deep within the well. It is mandatory to drill the hole, in situ, in order locate the discharge at the proper depth. Other examples include the need to connect piping together in a water supply system or in a sanitary sewer system.
In the past, the practice was to initially drill a small pilot hole in the pipe and then drill a larger hole with the appropriate size drill bit. This arrangement caused numerous problems especially in terms of the precision in forming the hole. In addition, the operation often resulted in damage to the existing conduit, injury to the operator, and/or other difficulties, such as broken hole saws, broken drill bits, excessive chips in the conduit and so forth.
A variety of devices have been developed specifically for cutting holes in pipes or similar conduits, such as well casings. Patents have been granted for a number of these inventions, including the following:
Doty, in U.S. Pat. No. 3,847,501, describes a drill and tap attachment for pipe clamps, particularly a collar puller for metal pipe and the like. Holes are drilled and tapped at intervals in the pie for attaching threaded nipples. The tapping attachment is adjusted by hand which, in turn, operates the drill and tapping unit. Only a small bit is used for drilling the pipe.
In U.S. Pat. No. 3,922,107, Fowler discloses a core drilling device for sewer pipes. The device includes a base secured to the pipe with bolts penetrating the pipe. A drill press type of stand holds a core drill that cuts the pipe through an aperture in the base. The bolts are used to secure a clamping plate that secures a branch pipe to the sewer pipe.
Hutton, in U.S. Pat. No. 3,976,091, describes a pipe tapping tool having a plug means adapted to fit internally within a branch pipe. A boring bar is mounted on the plug means so as to be capable of being linearly or rotatably moved with respect to the plug means and so as to extend through the plug means. A boring means is mounted on one end of the boring bar. A mounting member is secured to the plug means and extends outwardly therefrom. A holding means carried by the mounting means secures the plug means to a branch pipe. The holding means comprises two interfitting yokes adapted to fit around the exterior of the branch pipe so that their extremities are locked together. A separate fastener secures the base of each of the yokes to the mounting means, the fasteners being located on diametrically opposite sides of the branch pipe when the tool is installed.
U.S. Pat. No. 4,005,945 by Gutman discloses a clamp and drill guide apparatus utilized by an operator to aid in manually drilling holes in work pieces, which have an arcuate contour. The apparatus includes a first clamping member, which has a multiplicity of openings axially passing through the first clamping member in a vertical direction. A second clamping member located in alignment with the first clamping member and below such, includes a multiplicity of threaded through openings, which axially pass in the vertical direction and are alignable with each of the through openings in the first clamping member. A pair of screw and nut members clamp the first member to the second member when a work piece is inserted there between. Further, the apparatus provides a mechanism for axially aligning the work piece between the first member and the second member.
In U.S. Pat. No. 4,094,612, Kring describes a plate having a flat surface for mounting the tool to an irregular or curved work piece. The plate has a plurality of depending legs forming a notch between them for straddling the work piece. Means for fastening the plate to the work piece include a roller chain attached to a threaded hook to adjust the length of the chain around a pipe.
Harris et al., in U.S. Pat. No. 4,152,090, describe an apparatus for cutting a hole through the sidewall of a longitudinally extending pipe. This apparatus includes a cylinder saw, i.e., a hole saw, and a portable jig for supporting and guiding the saw during the hole cutting operation. The jig pivots to allow the hole saw to enter the pipe at an angle to begin the hole cutting operation.
U.S. Pat. No. 4,422,812 by Linville discloses a rotatable shell cutter having a cylindrical member which advances to cut into a pipe. A plurality of cutting elements is arranged in a circle at one end of the cylinder. Each cutting assembly comprises a cartridge fixed as one piece to the cylindrical member, such as by brazing or the like, a seat positioned thereon through dowel pins, a cutting insert mounted on the seat through a cooperating V-shaped projection and recess, and a clamp engaging, positioning and securing the cutting element against the seat and also secured to the cartridge for urging all of the cutting assembly elements together. The clamp is fitted for a particular sized pipe.
Dolatowski et al, in U.S. Pat. No. 4,936,720, describe a device for cutting holes in pipe that includes a base configured for attachment normal to a section of pipe and having a track extending the length of the base. A travel plate is slidably engaged in the track and configured for the accommodation of a power drill thereon. A mechanism controls the linear reciprocal movement of the travel plate in the track, the length of the base being just long enough to accommodate the drill and hole drilling bit assembly for operating the apparatus in close quarters. A hole locator, and an adapter for attachment of the base to smaller diameter pipes may also be provided.
U.S. Pat. No. 5,051,044 by Allen discloses an apparatus used to drill holes in existing pipes or other conduits, or virtually any cylindrical object. The apparatus includes a mounting unit which rests upon the pipe to be drilled and a drill mounting apparatus. The drill mounting apparatus is removably mounted to the mounting unit. The drill mounting apparatus is adapted to receive and position a drilling device which forms a hole in the pipe or the like.
In U.S. Pat. No. 5,163,792, Slavik describes a clamp structure that mounts a workpiece between an underlying saddle plate and an uppermost bushing head. The bushing head includes a slidably received guide bushing directed there within in coaxially oriented alignment, with a saddle bore directed within the saddle to provide for alignment of drilling directed through the workpiece. The invention further includes the bushing head and a saddle clamp arranged and mounted on pivoting jaw structure arranged for clamping the workpiece there between.
Cooper, in U.S. Pat. No. 5,800,099, describes a system for using a portable tool for assisting the making of holes in installed pipes, such as water pipes and the like, to prepare for interconnected piping. The system preferably utilizes a hole saw guide bushing, which is contained in a clamp-head at the end of the fixed jaw of a “Vise-Grip”-like device. The clamp-head accommodates various sizes of guide bushings and hole-saws for making various size holes in various size pipes. Other features assist accurate hole positioning, e.g., horizontal and vertical levels, center marks, and V-shaped holding surfaces on the clamp-heads.
U.S. Pat. No. 5,879,112 by Ivey discloses a water supply line tapping tool for allowing plumbers to tap into a main water supply line. The device includes a main shaft having a first end and a second end. The first end is adapted for coupling with a standard portable electric drill. The main shaft has a threaded hole therein disposed inwardly of the second end. The threaded hole receives a screw therein. The second end has an internally threaded receiving collar disposed thereon. A hole saw is coupled with the receiving collar on the second end of the main shaft. The hole saw has an arbor portion. The arbor portion has an internal end extending inwardly of the second end of the main shaft for being engaged by the screw extending within the threaded hole. A sleeve is slidably disposed on the main shaft for coupling with a saddle valve.
In U.S. Pat. No. 6,050,753, Turner describes an apparatus for mounting a drill on the pipe.
The apparatus includes a platform carrying a mounting member for a drill stand. The mounting member slides along a frame which carries a plurality of elongated holes therein. The longitudinal movement allowed by sliding permits a drill mounted on a drill stand to be selectively positioned to bore a hole in a pipe upon which the platform is rigidly clamped. By provision of such a facility, there is no need to loosen the clamping force of the platform upon the pipe.
Turner, in U.S. Pat. No. 6,761,511, discloses a V-shaped frame attached to a pipe to be drilled. The frame may be used with larger pipes by attaching a removable extension plate to the arms of the V-shaped frame, thereby increasing the size of the recess between the arms. The apparatus may be fixed to the pipe by a chain, which connects to the platform and extends around the pipe, or by attaching clips to the frame and attaching the clips to the surface of the pipe by screws, etc.
U.S. Design Pat. No. D 499,002 by Troxell shows a universal guide for a hole saw. The guide appears to include a suction cup device for attaching the guide to a surface and an adjustable portion having overlapping plates, each with a V-shaped opening. The hole saw fits into the square opening formed by the overlapping plates.
Applicant has devised a hole cutting assembly useful for cutting relatively large diameter holes in well casing, pipes and similar conduits which have a generally circular cross section.